Different stropping compounds?

[yepimonfire]

Been stropping using white rouge, any point in using something like green compound? I'm looking to get the sharpest possible edge.

Side question, what is the order of fineness in compounds based on color? Red, blue, white, green?

 

[Obsessed with Edges]

Been stropping using white rouge, any point in using something like green compound? I'm looking to get the sharpest possible edge.

On something like 1095, I've often followed the white rouge with just a few (< 5) passes on green, used on a leather belt as a hanging strop. I've also liked this routine with 420HC. Gives it an extra 'nudge' into tree-topping, hair-popping sharpness.

Side question, what is the order of fineness in compounds based on color? Red, blue, white, green?

I'd look at it in terms of aggessiveness, versus only fineness. Sometimes a larger grit will work less aggressively, if it's either softer or differently shaped (or both). For example, red compound will likely be somewhat larger in particle size, but nowhere near as hard or aggressive as chromium oxide (green) or some 'white' compounds in aluminum oxide (also more aggressive than green, BTW). I think the 'blue' is usually a very fine aluminum oxide (may be called a 'rouge').

Given your list, I'd likely rank them this way, from most aggressive to least aggressive:

white (if AlOx) > blue (assuming AlOx) > green > red.

Red compound ('red rouge', a.k.a. iron oxide) is usually used for softer metals, like jewelry. Many modern cutlery steels will be harder than red, so it's often not very aggressive, and even ineffective on knife edges. A bare leather strop would likely work as well, maybe better.

Some 'white' compounds will be something like tin oxide or even talc, which are less aggressive even than the red compound, used for polishing things like jewelry or plastics.


David

 

[yepimonfire]

On something like 1095, I've often followed the white rouge with just a few (< 5) passes on green, used on a leather belt as a hanging strop. I've also liked this routine with 420HC. Gives it an extra 'nudge' into tree-topping, hair-popping sharpness.



I'd look at it in terms of aggessiveness, versus only fineness. Sometimes a larger grit will work less aggressively, if it's either softer or differently shaped (or both). For example, red compound will likely be somewhat larger in particle size, but nowhere near as hard or aggressive as chromium oxide (green) or some 'white' compounds in aluminum oxide (also more aggressive than green, BTW). I think the 'blue' is usually a very fine aluminum oxide (may be called a 'rouge').

Given your list, I'd likely rank them this way, from most aggressive to least aggressive:

white (if AlOx) > blue (assuming AlOx) > green > red.

Red compound ('red rouge', a.k.a. iron oxide) is usually used for softer metals, like jewelry. Many modern cutlery steels will be harder than red, so it's often not very aggressive, and even ineffective on knife edges. A bare leather strop would likely work as well, maybe better.

Some 'white' compounds will be something like tin oxide or even talc, which are less aggressive even than the red compound, used for polishing things like jewelry or plastics.


David

Would you say green will impart a finer edge than white?

 

[Obsessed with Edges]

Would you say green will impart a finer edge than white?

On less wear-resistant steels (1095, 420HC, 440A, etc.), most of the time it will, as compared to the most common 'white' stick compounds. This is why I've liked following my white rouge (Ryobi; 2-5µ) with green (0.5-1µ) on these steels. Some very fine (sub-micron) 'white' compounds could do just as well, however.

On more wear-resistant steels like D2 or S30V and similar, green often won't be hard enough to handle the carbides in the steel, and a rounded-over and therefore less-fine apex will eventually result. On D2, the white will do much, much better (and maybe the blue, if it's AlOx); on S30V, a diamond or CBN grit at 1µ or smaller would do much better. This is when the hardness of the grit becomes much more important than the size, within some limits.


David

 

[yepimonfire]

Would 1µ diamond paste impart a finer finish then green or white buffing compounds?

 

[Obsessed with Edges]

Would 1µ diamond paste impart a finer finish then green or white buffing compounds?

On what steel?

As mentioned in my earlier post, it depends somewhat on the wear-resistance of the steel. On steels with heavy vanadium carbide content (S30V, S90V, etc.) the 1µ diamond likely would produce a finer and sharper edge than either the green or white compounds, which won't abrade or shape the vanadium carbides as well. On a less wear-resistant steel like 1095 or 420HC, the white would very quickly thin the edge, and the green would do a better job refining it. All of this is assuming the strop is very firm and technique is good.


David

 

[Sadden]

If your looking for "The sharpest edge possible" trash the mystery sticks and get precisely graded products. "Green" is equal to neither 0.5u or 1u , most manufacturers have no clue what is in their stick color based products.

If you want to get as sharp as physically possible you have a ways to go.

Start with a high quality steel. S90V ,K390 etc
Add a good heat treat
Go as steep as the steel can possibly handle (takes some experimenting)
Start with some Atomas or other name brand diamond plates
Overlap with a high quality stone (Shapton , Chosera , Nubatama)
Take into account carbide size and enhance with CBN/Diamond as needed
After your final stone start stropping using nanocloth or kangaroo
Strop as fine as your heart desires ,160,000grit is a good start. (0.1u)

This is assuming your familiar with apexing an edge cleanly (with no residual burrs) , running a tight progression of stone (no skipping any) , and are checking your work with a microscope to make sure theres no residual scratches from each and every stone.

Thats a good start anyways.

 

[HeavyHanded]

With all due respect, I've taken a look at a number of "crayon" type compounds under microscope, and the better brands are surprisingly uniform in size distribution. The end seller might not know exactly what is in there, but the manufacturer surely does.

The Formax Green CrO sold at Woodcraft is extremely tight in this regard and even the finer white compound from Ryobi is very uniform. Many of the general purpose compounds or ones made for wood carving tend to have a distribution range but this is intentional in most cases - the Formax green made for Lee Valley has several size abrasives as does Flexcut Gold - this strategy works better for making and maintaining finer working edges compared to a single grit size compound.

To the OP, diamond is a good bet for overall utility and if you don't want to stock multiple abrasives and may have high Vanadium carbide content steels in your inventory.

For carbon steels and the less expensive or lower vanadium content stainless, Aluminum Oxide based compounds will work very well, generally better (IMHO) than diamond compounds. The CrO tends to be a bit more fickle but still works great on carbon steels and many types of stainless.

Silicon carbide is not commonly used in stropping compounds, but when used in this mode it works very well even on large non-Vanadium carbide steels like 440C and D2. A handy source of this can be had simply by reclaiming the slurry that forms on a SiC stone when worked with oil. Will not be the finest grit, but works very well for EDU and if carefully managed can create surprisingly refined edges.

The goal of "sharpest possible edge" can have different meanings depending on what the edge is being used for, and this will determine what sort of edge finish you might want to use. Max refinement is not always a good investment in time, depending. YMMV

Martin

 

[yepimonfire]

Where can someone find diamond paste that fine? I've searched and searched and found no lower then .5 micron

All steels used are
Sk5
Aus 8a
8cr13mov
1055 carbon
Mystery kitchen

Nothing high end, afaik the only thing with high amounts of vanadium carbides is the Aus 8a and 8cr13mov.

Mystery white crayon has managed to abrade them all.

 

[Obsessed with Edges]

Where can someone find diamond paste that fine? I've searched and searched and found no lower then .5 micron

All steels used are
Sk5
Aus 8a
8cr13mov
1055 carbon
Mystery kitchen

Nothing high end, afaik the only thing with high amounts of vanadium carbides is the Aus 8a and 8cr13mov.

Mystery white crayon has managed to abrade them all.

Actually, those two don't have significant vanadium carbides in them either. Many steels will have small amounts of vanadium alone (usually well below 1%, added for grain refinement). But, until the vanadium gets up to around 2-3% or higher, AND if there's more than 1-1.5% carbon, vanadium carbides won't form in enough mass to make a difference. Compare to S30V with ~1.5% carbon and 4% vanadium; lots of building blocks for hard vanadium carbide there. AUS-8/8Cr13MoV are generically very similar, and neither has more than about 0.8% carbon (half that of S30V) and 0.25% vanadium (1/16th that of S30V).

Your white and green compounds should handle all the steels you listed, quite easily; you're seeing that already, with your 'mystery white crayon' results. Diamond or CBN at very fine grit can also work, but they'd essentially be overkill on these steels, and unnecessary.


David

 

[David Martin]

I have reclaimed grit from SiC stones during sharping and leveling. Then applied this to a leather strop and it will work to restore the edge. It is slow requiring 200-300 passes to restore the edge but it does work. DM

 

[Sadden]

With all due respect, I've taken a look at a number of "crayon" type compounds under microscope, and the better brands are surprisingly uniform in size distribution. The end seller might not know exactly what is in there, but the manufacturer surely does.

The Formax Green CrO sold at Woodcraft is extremely tight in this regard and even the finer white compound from Ryobi is very uniform. Many of the general purpose compounds or ones made for wood carving tend to have a distribution range but this is intentional in most cases - the Formax green made for Lee Valley has several size abrasives as does Flexcut Gold - this strategy works better for making and maintaining finer working edges compared to a single grit size compound.

To the OP, diamond is a good bet for overall utility and if you don't want to stock multiple abrasives and may have high Vanadium carbide content steels in your inventory.

For carbon steels and the less expensive or lower vanadium content stainless, Aluminum Oxide based compounds will work very well, generally better (IMHO) than diamond compounds. The CrO tends to be a bit more fickle but still works great on carbon steels and many types of stainless.

Silicon carbide is not commonly used in stropping compounds, but when used in this mode it works very well even on large non-Vanadium carbide steels like 440C and D2. A handy source of this can be had simply by reclaiming the slurry that forms on a SiC stone when worked with oil. Will not be the finest grit, but works very well for EDU and if carefully managed can create surprisingly refined edges.

The goal of "sharpest possible edge" can have different meanings depending on what the edge is being used for, and this will determine what sort of edge finish you might want to use. Max refinement is not always a good investment in time, depending. YMMV

Martin

Thats fine Martin. My main point being that "green" is not a measurement of particle size. Neither is "white". The notion that any old green bar from the hardware store is automatically equal to 0.5u is a serious piece of misinformation that gets propogated around here.

I actually bought the flexcut strop kit based on your reccomendations because its one of the few I havent tried. I have some initial impressions but am going to be taking a more serious look at it when i get home from work this weekend.

And if your looking for the absolute best bar compound....
https://www.sharpeningforum.com/index.php?option=com_kunena&view=topic&catid=4&id=273&Itemid=101
They arent quite out yet ,but these will blow the doors off of anything currently on the market. By a very wide margin indeed.

 

[Obsessed with Edges]

(...)
And if your looking for the absolute best bar compound....
https://www.sharpeningforum.com/index.php?option=com_kunena&view=topic&catid=4&id=273&Itemid=101
They arent quite out yet ,but these will blow the doors off of anything currently on the market. By a very wide margin indeed.

Can't help but think the price tag of the 'Diamond Bars' will blow the doors off too, if they're as loaded with diamond as described; scares me to think of it.

Interesting, nevertheless.


David

 

[David Martin]

I wouldn't doubt that! DM